This is where drug dealers take the cheap, plastic Bic lighters and take them apart. Wash them out and rig them to put crack and coke in them. They would fill them up and sell them individually like you would do in baggies, only when you're holding a lighter it looks less suspicious than holding a bag or vile. They would just pass them off, hand to hand
or someone would ask to borrow a lighter. Hence 25 lighters means someone's got 25 viles to sell, hence the "Got's to get paid" part.

John: Man, that my jam. DJ DMD, Fat Pat and Lil Keke all went hard on "25 lighters". That shit is a dirty south classic!

Xav: Damn right shawty, "25 lighters on my dresser, yes sir, I got to get paid".